The invention relates to a device for tying-up an animal with:
a suspension element to be hung at the top to a fixed structure,
a bottom yoke which can be connected to the fixed structure,
two legs which lie between the suspension element and the bottom yoke, and which form together with the bottom yoke, one yoke, which legs are each comprised of
a top part which hinges in the suspension element about an axis which lies at right angle to the main yoke plane and PA1 a lower part which hinges through a first hinge in the top part, and through at least one other hinge is connected to the bottom yoke, which hinges allow a motion in the main yoke plane and outside thereof,
means which retain in the one end position, the top parts in a closing position, and in the other end position thereof, retain the top parts with the top ends thereof facing one another, in an open position, and
a bolt which locks the legs at the top relative to one another, in the closing position.
Devices of this kind are particularly intended for tying-up cows.
A device of this kind is known from Belgian Pat. No. 885,292.
In this known device, as in the device according to the invention, both lower parts and both top parts of the yoke form in the open position of the yoke, a parallelogram with a horizontal diagonal in the crosswise direction of the lying-and-standing station wherein the yoke is hung.
The passage from the open position to the closing position is obtained by shortening this horizontal diagonal and consequently by lengthening the vertical diagonal of the parallelogram, which also brings said means from that outermost position wherein they retain the top parts of the yoke legs in open position, to that position wherein they bring said top parts in closing position.
In open position, wherein the vertical diagonal is shortest, the flexible elements, generally chains, with which the suspension element is hung from the fixed structure and the bottom yoke is connected to the fixed structure, actually the floor, may be stretched.
This is the case with the known device according to Belgian Pat. No. 885,292, in which the passage from the open position to the closing position is exclusively caused by the animal entering the lying-and-standing station and wanting to eat from the crib, which lies on the other side of the device relative to the side the animal comes from, pressing the bottom yoke or the lower parts of the yoke legs towards the crib.
The yoke is thus pressed towards the crib, but as the flexible elements which connect the bottom yoke and the suspension element to the fixed structure, are stretched in the open position of the yoke, this is possible but as the vertical diagonal of the parallelogram becomes longer. With a long enough lengthening of the vertical diagonal, said passage occurs. The lengthening of the vertical diagonal is dependent on the distance over which the animal pushes the yoke frontwards, but also on the length of the flexible elements. The longer such flexible elements are, the farther the yoke has to be pushed frontwards to cause the change in position, that is to bring those means which in the one end position thereof, retain the top parts in open position, and in the other end position thereof retain the top parts in closing position, to the balance position wherein they pull neither to the one nor to the other end position.
For a given lying-and-standing station, the spacing between the fixed structure at the top, for example a top beam, to which the flexible elements which bear the suspension element can be hung, and the floor of the fixed structure to which the bottom yoke is connected, is fixed, so that for a given device and a given lying-and-standing station, the length of the flexible elements is not freely selectable.
With a great height of the top beam above the floor, the flexible elements also have to be long, in such a way that the yoke has then to be pushed quite far and possibly over the crib to pass from the opening position to the closing position. Whether the animal will push the yoke far enough to close same depends on the location where the animal finds the feed which is arranged on the other side of the yoke relative to the entering position. The feed cannot be located in every lying-and-standing station far enough from the yoke for the animal to cause enough displacement of the yoke to close same, with the result that the known device according to Belgian Pat. No. 885,292 may not be applied everywhere.
Moreover, in said known device, the means which in the one end position thereof, retain the top parts in a closing position, and in the other end position thereof, retain the top parts in open position, have to be arranged very accurately, which is not always possible in practice, so that the operating reliability of the device leaves something to be desired in some conditions.
A drawback of the device according to the Belgian Patent is further that said device does not always close when animals come in which are of small build.